Highly toxic pollutants in the urban metropolises result in increasing cardio vascular problems and chronic respiratory diseases. But they also seriously affect a vital organ - the eye.
The results of a study done in Delhi on people exposed to high level of air pollution due to vehicular traffic shows 78 per cent complaining of redness, watering, irritation, strain in the eyes, and photophobia.
The most striking result shows intolerance to light or photophobia increased by more than six times in the regular travellers in the polluted city areas.
The study supported by the Ministry of Science and Technology was carried out with help of doctors at the Delhi Institute of Pharmaceutical Sciences and Research, Venu Eye Institute and Research Center, and Dr Rajendra Prasad Center for Ophthalmic Sciences, AIIMS.
It compared the symptoms of people who commuted daily via highly polluted areas for at least two years (study group), to those who did not travel long distances on a daily basis and lived on residential campuses and also went to workplace within the campus (control group).
Five hundred and twenty persons were examined by eye doctors. Four hundred and forty one were part of the study group and 79 were part of the control group.
The results of the study showed that while there was no significant difference in the vision of both groups, symptoms of redness, watering, irritation, strain, blurring and photophobia were absent in 55 per cent of people in the control group, only 22 per cent people in the study group were without any symptoms.
For the people who lived and worked within a campus and travelled less, only 22.44 per cent of them suffered from watering, 20.40 per cent from irritation and 24.49 per cent from strain.
However, in the regular travellers through polluted areas, the figure of the symptomatic persons almost doubled. Nearly half of the study group (49.21 per cent) suffered from watering, 43.99 per cent suffered from irritation and 45.12 per cent from eye strain.
Whereas only 14.28 per cent in the control group complained of occasional redness of eyes in the study group the figure jumped to 38.22 per cent.
While only 2.04 per cent people in the control group suffered from photophobia or intolerance to light as high as 13.82 per cent of study group suffered from it.
The study claimed acidification of tears by high levels of oxidants like nitric oxide, nitrogen dioxide, sulphur dioxide in polluted air might be responsible for the symptoms.
The results of study have been reported in the latest issue of the Indian Journal of Occupational and Environmental Medicine.
Eminent eye surgeon Sudiopto Pakrasi of Aashlok Hospital said, "All eyes are lubricated with naturally forming tears to keep them from drying. Tears maintain a clear surface for refraction of the light entering the eye and also contain anti bacterial agents, which help avoid infection by normal germs."
He said that this 'highly fragile' tear film can be adversely affected with pollutants like sulphur dioxide, nitrogen dioxide, nitric oxide making the tear film acidic and highly unstable resulting in the dryness of the cornea.
The acidification causes local irritation of the surface of the tissues of the eye resulting in redness of the eye, irritation and watering tendency, he added.
"It is because of lack of adequate lubrication of the cornea which causes dryness. The superficial corneal nerves get irritable resulting in photophobia or intolerance to light," he said.
These symptoms do not cause any permanent loss of vision or deformity in the eye but results in chronic irritable eye causing constant discomfort to people, he said.
"A common misconception is that sunglasses will help prevent the eye from pollution. It does not, as pollutants in the air enter the eyes from the sides. Aviator glasses might help but they are impractical. The only solution for regular travellers lies in using tear film supplement drops to keep the eye lubricated," he added.